Mating Instinct
by Jack Solo Black
Summary: The Doctor gets caught unawares by a biological trait... Jack just happens to be there...


Mating Instinct.

"Hey Jack, could you pass me that... Agh!" The Doctor gasped suddenly and doubled over, and Jack looked at him, concerned.

"Whoa! Hey, you okay?"

"Agh! Yeah, I think... Gah!" The Time Lord's knees hit the floor and he swallowed short, ragged breaths as a sharp pain suddenly shot through him, leaving him breathless and shaken. '_What in the name of Osiris...?_' He thought, but was interrupted as another stab of pain flared through him, slightly stronger now and more persistent.

"Oh, shit!" The Time Lord swore, as he suddenly realised what this meant. "No! No, no, no, no, no, no, no! No, I can't! Not now! Not... Aaagghh!"

"Doctor, what is it?" Jack asked. He was on his knees squatting beside him now, concern etching his features.

The Time Lord was breathing heavily now, and he looked up at Jack with a slightly crazed look in his eyes, and shook his head. "It's... It's nothing... It's... Gah!"

"Well, obviously it's not 'nothing' or you wouldn't be on the floor." Jack said, pointedly. "So tell me."

The Doctor shook his head again, gritting his teeth. "I can't... It's..." He gasped again.

"What?"

"It's... Well, actually it's... kind of... embarrassing... and a little unconventional right now..."

"Huh? What's that supposed to mean?" The immortal asked, "Unconventional how?"

"It's... It's... It's... Gah! It's..." He paused for a moment, steeling himself, then ground out; "It's... a biological thing... a Time Lord thing... It's... a throwback... a sort of... physiological failsafe... so to speak... Survival of the species... that sort of thing... but... Agh! It can't... I can't... Aaghh! I mean, this shouldn't... shouldn't be happening... Not now... it's not supposed... to happen... yet... it's too soon... I'm not... Gaaahhh!"

"What do you mean by 'fail-safe'?" Jack asked.

"Basically... I mean... it's... agh! It's sort of a... a... mating instinct... Sort of a... biological egg timer... it... kicks in every... two-hundred years or so... but, it's early... I shouldn't... Aaagh!"

"So, basically, you're in heat?" Jack asked, half smiling at him.

"Jack... Stop it..." The Time Lord said, but he nodded an affirmative to his query.

"So... apart from the obvious, what can you do about it?"

"Nothing... just... nothing... Jack..." The Doctor grabbed his hand suddenly, holding his gaze, and he said seriously; "Jack... If I don't... if I can't... mate... it'll kill me..."

"But you'll regenerate, right?" The immortal asked, hopefully.

The Time Lord shook his head. "No... Not from this... I mean... it'll really kill me... properly... for good... and I can't... Aghh!"

"What?" Jack asked, softly now.

"I'm scared, Jack... Terrified... I don't want to die... Not yet... not... not like this..."

"You won't." Jack insisted.

"Jack..." The Doctors' voice sounded distant now, as he said slowly; "I can't control it... once it starts... once it reaches fever-pitch... I won't be able... to stop myself... if there's... someone around... anyone... Jack... you understand? You have to leave... now... before I... before..." He shuddered violently and a high, keening whine left him and he started to shake, uncontrollably.

Jack reached out a hand, and the Time Lord jerked back, away from him.

"Don't... Please don't... Don't. Touch. Me... You'll only make it... worse..." His blood was on fire now, hearts racing, and with Jack sitting so near him the Time Lord could smell the faint tinge of desire coming off him even more acutely than normal...

"Y'know, if that's all it is, Doctor, I'd be quite happy to help..."

I know you would, Jack... but it's not... it's not... that simple..."

"Why not?"

"Because... if we... if I... It's not just... 'mating' Jack... It means... _mating_... as in..."

"Oh! You mean that if I save your life, you're gonna be stuck with me?" He looked annoyed for a moment.

"You'll be stuck with me..." The Time Lord corrected. "Forever... Which... for you... could be a very... long time..."

"I wouldn't mind being stuck with you." Jack said, grinning slightly despite himself.

"You might... I'd change, Jack... I'd become... possessive... territorial... domineering... you couldn't... no one else, Jack... No one... Not ever..."

Jack was serious again now. "I'd give that for you in a heartbeat, Doctor... I'd give everything... All you have to do is ask..."

"You may not have a choice... if you don't... go... now..."

Jack shook his head. "I'm not leaving, Doctor. I already made my choice a long time ago..."

The Doctor was drenched in sweat now and still shaking, and he could smell Jack's arousal for him tenfold, sparking the ancient instinct like an electrical current through his blood, and he knew he couldn't hold it for long...

Jack reached his hand out again, and the Time Lord tried to move back.

"Jack... Don't..." The immortals' desire shot through him like lightning, and his skin burned, and his body hungered and ached to end it... to stop the burn, and take a mate... Any mate...

The Time Lord practically howled when Jack's hand stroked his face, softly, and just that small contact was his undoing.

He leapt at Jack suddenly, slamming the immortal to the floor, growling slightly in feral need, unceremoniously ripping his clothes off, stripping his own surprisingly quickly, and he kissed Jack, fiercely, shoving his tongue in his mouth forcefully, tasting him, before suddenly flipping him onto his front, pulling his hips up, and biting and nipping at his neck as he suddenly thrust in, without warning.

Jack let out a short scream, not quite prepared for the swiftness with which the mating instinct seemed to take hold, and he was glad he healed fast because the hard, unprepared entry had hurt like hell!

The frenzied Time Lord didn't even give him time to recover before he started moving, fast, erratic strokes at first, and Jack grunted, then gasped loudly as the pain faded, and the Doctors' strokes got longer, deeper, and he was panting and grunting in Jacks' ear now, leaning right over him, claiming him properly...

He didn't last more than a few minutes the first time, but Jack could tell he was nowhere near finished yet. The Doctor stayed where he was, panting and shaking for a moment, his breath hot and heady at the immortals' neck, and Jack groaned slightly, suddenly deigning to wonder just how long this 'mating' thing could possibly last for? He knew some species could stay in heat for days on end, and he also knew that the Time Lord didn't need to sleep very much. He just hoped that if that was the case, his over-active libido could actually keep up with the Time Lords' boundless energy. He was only human, after all. Immortal, maybe, and a little more hardwearing than most of his species – but still human nonetheless.

The Doctor started moving again, a little slower this time, and now Jack had time, after the initial, sudden fervour of it all, to really appreciate the feel of the Time Lord moving against him, inside him. He wasn't particularly used to being jumped on as he was usually the one doing the jumping, but in this particular instance he wasn't at all complaining.

The Doctors' lean body was hot and firm, and the immortal could feel the tightly corded muscles rippling beneath his burning skin, harsh grunts and pants sounding in his ear. His length was long and thick, and rather pleasantly filling, and Jack groaned loudly and dropped his head forward onto his hands, relishing the feel of his Time Lord owning him, rutting into him fiercely, desperately, guttural, needy moans and small animal-like growls issuing from him as he let the mating instinct ride him, hard and hot, and Jack gasped, and moaned loudly at the knowledge that he really was _his_ Time Lord now...

"Ugh! Doctor!" The immortal cried out, sharply, and arched his back, fingers clawing at the metal grating of the TARDIS floor as the Doctors' cock hit his prostate, and the Time Lord growled softly at his throat, and angled his thrusts, liking the deliciously lustful sounds his willing human was making.

He breathed in deeply, and Jacks' scent was thick and sweet and rather musky, and the Doctor committed it to memory, along with the feel of the immortal human writhing and shaking beneath him, his walls contracting pleasantly around his hardened member, the small cries falling from him as the Time Lord claimed his mate, fully, and he let out a high pitched, keening howl when he felt Jack spasm and jerk beneath him, a loud shout leaving the immortal as he came, hard, and the sound of his own name falling from his mates lips as brought him sent a satisfied shiver down the Doctors' spine, as he filled the gasping, panting human with his hot seed for the second time that hour...

The Doctor took him repeatedly for the next few hours, and eventually found himself staring down at Jacks' naked and sweating form, eyes glazed over, on his back, the cool metal of the TARDIS floor cooling his heated skin as the Time Lord shook his head as if to clear it, looking down at him a little concerned, as the urges started to fade, leaving him feeling rather very satisfied and even a bit triumphant. He was also rather glad not to be dead, although...

"Jack..."

"Hey... I gotta say, the running definitely does you some good..."

"Yeah... Are you alright?"

"Oh... yeah, I'm fine. Great, actually... Really great."

"You look like you just went ten rounds with a rabid werewolf..."

"I feel like I just went thirty rounds with an insane Time Lord... In other words; great... A little tired, and just a wee bit sore, but otherwise, great."

"Heh. You're lucky you're immortal, Jack. Most humans definitely don't have a Time Lords' stamina."

"Good thing I'm normal then, isn't it?"

"Yeah... Maybe you're not so wrong after all..."

"Huh? Was that an apology?"

"It was a... change in judgement..."

Jack grinned slightly. "You're forgiven."

"Thanks, and... thanks for not... letting me die."

"Heh. You're welcome. Very welcome, actually."

"There's still one thing I have to tell you..." The Time Lord said, seriously.

"What's that?" Jack asked, cautiously.

The Doctor leaned down to whisper in his ear, quietly, fingers splayed at his temples, and Jacks' eyes went wide and astonished.

The Time Lord had a strange grin on his face as he pulled back to look at him, and he said conversationally; "Don't tell anyone."

Jack just nodded his head in agreement, as the Time Lords' mind opened up to him, and he could see everything he would ever want to know about his Doctor...

As the Time Lord moved off him to find his clothes, the immortal smiled to himself, and said inaudibly; "Thank _you_, Theta..."


End file.
